Were humans only rational creatures, we'd have no need for valentines, or love songs, or many personal finance columns. When it comes to both love and money, emotions often rule the mind -- for better and for worse.

Using your emotional brain can work for you or against you when it comes to managing your finances. Stand back a little bit from yourself to figure out whether your feelings will motivate action or cause you to sink into despair.

Guilt: Guilt can be your worst enemy when it comes to money, causing you to ignore problems and let them fester. You'll recognize this emotion as the sinking feeling in the pit of your stomach when your credit card bill arrives and you bury it under a pile of old newspapers, hoping it "accidentally" gets recycled. Or maybe an empty savings account is among your triggers. However, a strong desire to purge that sinking feeling may be just what you need to jump into action and develop a plan to tackle whatever financial problem you've been ignoring.

Fear: When it comes to money, there's much to fear. Will you have enough for retirement? Will you be able to afford to send the kids to college? Will housing prices go up or down? What does the future hold? You won't know what the future holds until it gets here. (If you do know, please pass along your stock tips.) In the meantime, use your fear to motivate you to act. Start planning today for what might happen tomorrow. Take a few extra steps to prepare for the unknown, and you'll sleep better at night.

Panic: Let the fear take over, and one day you wake up in a cold sweat, certain that you'll default on the mortgage, lose your job, and have nothing left but your dog and your old collection of Beatles albums. If you're gripped by panic due to general fear or a major change like a divorce or job loss, take a moment before making any financial decisions. You may make decisions you'll regret later if you fail to engage your rational mind.

Boredom: It can drive you to eat too many chips while watching television, and it can also drive you to spend too much money in search of entertainment. Become attuned to the times that boredom causes you to pull out your wallet or credit card, and you'll probably discover a major source of overspending. Whether it's a new pair of shoes, an electronic gizmo, or a new piece of jewelry, recognize that everything new eventually becomes yesterday's thrill. It won't relieve your boredom forever.

Envy: Those Joneses. Aren't you sick of it? They always have the latest SUV parked in the driveway. Mrs. Jones always wears the latest fashions. Baby Jones has the fanciest stroller on the block. That's it, just march on down to the car dealership and show those Joneses that you can have the good life, too. Don't you feel better now? At least until the credit card bills arrive, or the new car payment starts putting a real dent in the monthly budget. That's the downside to purchasing out of envy -- you hurt only yourself. The Joneses probably don't even notice. Start envying the Smiths' six-figure retirement accounts, and then you'll be motivated in the right direction.

Joy: Weddings, birthdays, babies, new homes -- life is absolutely full of joyous events that make you appreciate everything. Tapping into this joy can be one of the best money saving tricks around. Who needs new gadgets when you have fabulous family and friends? On the other hand, these joyous events can also mean lavish parties, fabulous presents, and massive redecorating or renovation projects, all of which can be expensive. Don't let your happiness make all the decisions for you; instead, let your happy brain ask your rational brain whether the celebration is affordable.

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Fool contributor Mary Dalrymple hopes you have a happy day, and she welcomes your feedback. The Motley Fool has a disclosure policy.